Locomotive draft appliance



Dec. 1 1923. 1,4727% A. .J.'TOWNSEND ET AL LOCOMOTIVE DRAFT APPLIANCEFiled Feb. 4, 1922 2 Sheets-Sheet 1 A TTORNE Y5 Dec. 18 1923. 11,477,736

A. J. TOWNSEND ET AL 1 LOCOMOTIVE DRAFT APPLIANCE 2 Sheets-Sheet 2 FiledFeb. 4 1922 I N VE N TORS A TTORNEVS Patented fies. l8, l923.

ALBERT J. TOVINSEIJD AND HERBERT W. SNYDER, OF LITIIA, OHIO.

LOCOMOTIVE DRAFT APPLIANCE.

Application filed February 4, 1922. Serial No. 534,155.

To all 1 :72am it may concern:

Be it known that we, ALBERT J. TOWN- SEND and HERBERT W. SNYDER,citizens of the United States. both residing at Lima, in the county ofAllen and State of Ohio, United States of America, have invented certainnew and useful Improvements in Locomotive Draft Appliances, of which thefollowing is a specification.

This invention relates to draft appliances and is particularly useful inconnection with steam railroad locomotives.

In standard locomotive practice, a stationary nozzle is employed, thearea through which the steam is discharged being constant so that thepressure required to force the exhaust steam through the nozzlecom monlycalled the back pressurebears a certain relation to the amount of steambe ing discharged. Such back pressure is low when a small amount ofsteam is being discharged through the nozzle, and correspondingly higherwhen larger amounts of steam are being used. Back pressures of materialamount are undesirable as they subtract from the power developed by thecylinders. Heretofore, various designs of variable nozzles have beenmade, such variable nozzles being operated, for the most part, by manualmeans so that the area of the nozzle may be altered as required inaccordance with the amount of steam being used, in order to maintain theback pressure within reasonable limits. The manually operated variablenozzles, however, have not gone into use for the reason that theirusefulness is comparatively negligible unless they are substantiallyconstantly being manipulated, for unless this were done the proper areaof nozzle would only be approximated. For practical considerations, itis impossible to properly manipulate the nozzles manually.

It is the purpose of our invention to provide an improved variableexhaust nozzle, the operation of which is entirely automatic and inaccord with the quantities of steam being passed through the cylinders,that is to say, the nozzle is operated in such manner as to maintain thedesired ratio of nozzle area to the amount of steam being used, therebypermitting a suitable regulation of the back pressure.

()ne of the primary objects of our invention, therefore, is to provide asimple and effective variable exhaust nozzle having the characteristicsand advantages described.

lVe accomplish the foregoing by means of a construction, the prelerredembodiments of which, are illustrated in the accompanying drawings,wherein:

Fig. l is a diagrammatic side elevation of a locomotive, illustratingthe application of our invention thereto; Fig. 2 is an en larged sideelevation and partial section, illustrating the working parts of ourimprovement; Fig. 3 is a partial end elevation and section of Fig. 2.

Our invention is based on the fact that there is a certain drop in steampressure between the boiler and the cylinders, and this drop in pressurebears a definite relation to the amount of steam being used. The steam,after'leaving the throttle, has to pass through the different steampipes to the cylinders, and, the area of these pipes being constant, itfollows that a certain amount of pressure is utilized in forcing thesteam through the pipes, the amount of this pressure increasing as moresteam has to be forced through the pipes. Thus, while the pressure atthe throttle will be maintained, the steam pipe pressure at thecylinders will be less, the difference being in proportion of the amountof steam pass ing through.

For the purposes of this specification, we have illustrated a variablenozzle device A which, in the position shown in Fig. 2, provides anozzle area of the size requisite to secure proper draft when the engineis using comparatively small quantities of steam. The nozzle area isincreased by moving the member 7 downwardly, which has the cifect ofcreating a space between such member and the outer member 8. By vir tueof the taper of the members 7 and 8, a relatively small amount ofvertical movement of the member 7 will provide sutlicient additionalnozzle opening to meetthe re quirements throughout the range ofoperating conditions.

F or operating the member 7 of the rariable nozzle device, we providethe following mechanism: The reference numeral 9 denotes an operatingcylinder preferably se cured to the smoke box shell in the mannerindicated in Figs. 2 and 3. Working in this cylinder is a piston 10, thepiston rod 11 of which is connected to the crank 12 by means of a link13 and stem 13. The crank 12 is fastened to a shaft 14: extendinginwardly into the smoke box and being provided at its inner end with asecond crank 15 which in turn operates the stem 16, the upper end ofwhich carries the member 7. Upward movement of the piston 10 from theposition indicated in Fig. 2 imparts a downward movement to the member7, increasing the area oi the nozzle opening. The piston 10 isnormallyheld in the position of Fig. 2 by means of the regulating spring17, the compression of which is adjusted by means of the nutlS. This nutis locked by a lock nut 19. To prevent the spring from jamming themember 7 against the member 8, a stop 20 is provided at the lower endor"- the piston rod. This step limits the downward movement of thepiston and its rod.

When the engine is working, pressure at the throttle is transmitted tothe lower part of the cylinder by means of the pipe 21 and the steampipe pressure is transmitted to'the upper part of the cylinder by meansof the pipe 22, the difference in these pressures placing an unequalload on the piston, torcing it upward against the compression of thespring. Since the rate of compression of the spring does not change, themotion of the piston is proportional to the difference in the pressure.Thus when the engine is only using a small amount of steam, the drop inpressure through the steam pipes is small, and the piston moves upwardlybut a slight distance. As more steam is used by the locomotive, the dropin pressure increases and the piston moves up farther, the motion beingtransmitted to the member 7 through the operating connections described.The area of the nozzl is thus kept at the proper size for the amount ofsteam which i being discharged. By adjusting the spring 1?, the ratio ofthe nozzle area to the amount of steam can be regulated so as to producewhatever back pressure is required to furnish adequate draft. Thusexcessive back pres sure is eliminated. At the same time the mechanismcan be altered so that it may be accommodated to different types oflocomo tives, different classes of service, and differ ent kinds of fuelor variations in quality of fuel.

lVe claim:

r 1. The combination in a steam locomotive,

of a variable exhaust nozzle and means for operating the same controlledby the drop in steam pressure between the boiler and the cylinders.

2. The combination in a steam locomotive, of a variable exhaust nozzle,and means for operating the same responsive to conditions in the steamline between the boiler and the cylinders. V

3. The combination in a steam locomotive, of a variable exhaust nozzle,and means for regulating the opening thereof as the locomotive is beingoperated, said means being automatically responsive to the variations inpressure conditions in the steam line to the cylinders as determined bythe amount of steam being used.

at. The combination in a steam locomotive, of a variable exhaust nozzle,and means for progressively adjusting the opening thereof as thelocomotive is being operated, said means being automatically responsiveto the variations in pressure conditions in the steam line to thecylinders as determined by the amount of steam being used.

5. The combination in a steam locomotive, of a variable exhaust nozzleand means for operating the same controlled by the drop in steampressure-between the boiler and the cylinders including a pistonsubjected on one side to substantially boiler pressure and on the otherside to substantially cylinder pressure.

6. The combination in a steam locomotive, of a variable exhaust nozzleand means for operating the same controlled by the drop in steampressure between the boiler and the cylinders including a pistonsubjected on one side to substantially boiler pressure and on the otherside to substantially cylinder pressure, and a spring'yieldingly holdingthe piston in the position securing small nozzle opening.

In testimony whereof, we have hereunto signed our names.

ALBERT J. TOWNSEND. HERBERT W. SNYDER.

